/**
* Writes the tag data.
*
* @param HausDesign_Io_Writer $writer The writer object.
* @return void
*/
private function _writeData($writer)
{
$this->clearOption('unsynchronisation');
$buffer = new HausDesign_Io_StringWriter();
foreach ($this->_frames as $frames) {
foreach ($frames as $frame) {
$frame->write($buffer);
}
}
$frameData = $buffer->toString();
$frameDataLength = strlen($frameData);
$paddingLength = 0;
// ID3v2.4.0 supports frame level unsynchronisation while
// ID3v2.3.0 supports only tag level unsynchronisation.
if ($this->getOption('version', 4) < 4 && $this->getOption('compat', false) !== true) {
$frameData = $this->_encodeUnsynchronisation($frameData);
if (($len = strlen($frameData)) != $frameDataLength) {
$frameDataLength = $len;
$this->_header->setFlags($this->_header->getFlags() | HausDesign_Media_Id3_Header::UNSYNCHRONISATION);
} else {
$this->_header->setFlags($this->_header->getFlags() & ~HausDesign_Media_Id3_Header::UNSYNCHRONISATION);
}
}
// The tag padding is calculated as follows. If the tag can be written
// in the space of the previous tag, the remaining space is used for
// padding. If there is no previous tag or the new tag is bigger than
// the space taken by the previous tag, the padding is a constant
// 4096 bytes.
if ($this->hasFooter() === false) {
if ($this->_reader !== null && $frameDataLength < $this->_header->getSize()) {
$paddingLength = $this->_header->getSize() - $frameDataLength;
} else {
$paddingLength = 4096;
}
}
/* ID3v2.4.0 CRC calculated w/ padding */
if ($this->getOption('version', 4) >= 4) {
$frameData = str_pad($frameData, $frameDataLength += $paddingLength, "");
}
$extendedHeaderData = '';
$extendedHeaderDataLength = 0;
if ($this->hasExtendedHeader()) {
$this->_extendedHeader->setPadding($paddingLength);
if ($this->_extendedHeader->hasFlag(HausDesign_Media_Id3_ExtendedHeader::CRC32)) {
$crc = crc32($frameData);
if ($crc & 0x80000000) {
$crc = -(($crc ^ 0xffffffff) + 1);
}
$this->_extendedHeader->setCrc($crc);
}
$buffer = new HausDesign_Io_StringWriter();
$this->_extendedHeader->write($buffer);
$extendedHeaderData = $buffer->toString();
$extendedHeaderDataLength = strlen($extendedHeaderData);
}
/* ID3v2.3.0 CRC calculated w/o padding */
if ($this->getOption('version', 4) < 4) {
$frameData = str_pad($frameData, $frameDataLength += $paddingLength, "");
}
$this->_header->setSize($extendedHeaderDataLength + $frameDataLength);
$writer->write('ID3');
$this->_header->write($writer);
$writer->write($extendedHeaderData);
$writer->write($frameData);
if ($this->hasFooter()) {
$writer->write('3DI');
$this->_footer->write($writer);
}
}
